This invention relates generally to assembly of microelectronic, optoelectronic and photonic components, and more specifically, to a component and chip assembly apparatus configured to optically couple optical fibers to light guides formed in a semiconductor chip.
In various technological fields such as photonics, for example, it may be necessary to attach a component having optical fibers to a waveguide coupler included with a photonic device. A cost effective approach to complete this attachment is to use a standard high throughput component and chip assembly apparatus typically referred to as a pick-and-place tool.
Standard pick-and-place tools include a picker mechanism that works to pick up the fiber component using a motion arm that includes a pick head. The picker brings the optical fibers into contact with a substrate or chip (i.e., the part the component will be placed on) which sits on a stationary assembly stage. The fiber component and the substrate/chip are then aligned in the X and Y-axes (e.g., horizontal axes) and the motion arm moves down in the Z-axis (e.g., vertical axis) to place the fiber component on the substrate/chip. The motion arm, however, typically does not have the capability to make a precise horizontal motion necessary to butt-couple the fibers and the waveguide coupler once the optical fibers come into contact with the chip. Moreover, even if such precise horizontal motion were possible, the motion arm does not generally have pressure controls in the horizontal displacement directions (e.g., the X and Y axes) in order to control the force of the butt-couple.
A conventional solution to provide the necessary horizontal motion is to pre-fix a fiber lid to the optical fibers using, for example, adhesive. That is, the optical fibers are fixed to the lid and are unable to move freely as the fibers are constrained by the adhesive as a function of the adhesive's compliance. Thereafter, the fiber component (having the lid already attached to the optical fibers) is picked up and maneuvered to the assembly stage such that the optical fiber/lid assembly is brought into contact with the chip. The assembly stage to which the chip is placed upon contains an angled sliding plane which converts some of the z-direction placement force to a horizontal force, pending on the angle of the sliding plane. This causes the chip to move towards the fiber component in the x-direction thus allowing the fibers to butt couple to the waveguide couplers on the chip. As the fixated fibers are first pressed into v-grooves on the chip to allow for proper alignment, the fibers apply a force to the v-groove walls thus creating a friction force (i.e. the sliding frictional coefficient) when the chip moves towards the fiber component and the fibers attempt to slide along the v-groove features.